What was the name of the building complex targeted by the Gunpowder Plot commemorated on Bonfire Night?

The Gunpowder Plot targeted the Palace of Westminster, the building complex containing the Houses of Parliament.

In 1605, the English Parliament met at the Palace of Westminster beside the River Thames. The conspirators planned to blow up the House of Lords during the State Opening of Parliament, when King James I, members of both Houses and senior officials were expected to gather.

Guy Fawkes was placed in a rented undercroft beneath the House of Lords with barrels of gunpowder. He was discovered there during a search ordered after the authorities received the Monteagle letter. The plan therefore failed before the king and Parliament assembled.

The medieval palace was damaged by fire in 1834, and most of the present Gothic complex dates from the nineteenth century. This can cause confusion when modern visitors picture the 1605 setting. Bonfire Night commemorates the failed attempt to destroy the earlier parliamentary buildings, not the later Victorian reconstruction.